Yeah the 8 million I mentioned is quite an outlier. Only mentioned it because it fell in the 20-30 range I suggested.

A quick and dirty copy/paste into openoffice calc shows since the last difficulty change, Ars has averaged about 1.55 million shares per block found with the Q1 and Q3 at 0.46m and 2.25m - I was using Ars as an example of a fair pool, the actual statistics seem to show they're beating the 1/difficulty rate by quite a bit(which explains the current positive buffer).

The accuracy gets a little screwy past the precision I'm using here because there was one data point that has a share count of 0 - not sure whether to include it or not, but the effect is like a -0.6% difference (1/170) if you include it(my numbers above don't).

[edit] oh just a thought, my math professors would kill me for saying 'average' when I meant 'mean', especially since I listed Q3 and Q1 - which are usually listed along with median for box plots. The median is 1.12mil, which shows the expected skew since numbers can't go below 0 but can occasionally get very high.

Don't forget that the difficulty is based on previous performance, to roughly get 2016 blocks per fortnight.

the Total Network Hashrate is now around 8-11TH/s, and the difficulty is still set for 14+TH/s hashrate (or thereabouts), and so there are fewer machines trying to find a harder number. It will take more than 2 weeks to get a new block cycle...by probably a week more, and the numbers you see will be normal until the new difficulty is calculated and then it'll go to something you're more used to.

If the number of machines mining drops further, to match price drops, it'll always take more than a fortnight, just like as hashrates have been increasing, it's always taken less than a fortnight.

Don't forget that the difficulty is based on previous performance, to roughly get 2016 blocks per fortnight.

the Total Network Hashrate is now around 8-11TH/s, and the difficulty is still set for 14+TH/s hashrate (or thereabouts), and so there are fewer machines trying to find a harder number. It will take more than 2 weeks to get a new block cycle...by probably a week more, and the numbers you see will be normal until the new difficulty is calculated and then it'll go to something you're more used to.

If the number of machines mining drops further, to match price drops, it'll always take more than a fortnight, just like as hashrates have been increasing, it's always taken less than a fortnight.

That's a good point. Average block time is rising due to the network being "underpowered". The reverse can also be true. IF network power is rising then aver block time will be less than 10 minutes until difficulty adjusts.